The present invention relates to a printer and, more particularly, to a stencil printer of the type wrapping a master around a print drum and pressing a sheet against the master with the print drum or a press drum.
Various kinds of sheet feeding devices have heretofore been proposed for use in a printer of the type described. One of them uses a sector gear for feeding a sheet from the top of a stack loaded on a sheet tray to a gap between a print drum and a press roller. The problem with the conventional sector gear scheme is that it cannot maintain the positional accuracy or registration accuaracy in the direction of sheet transport, an needs a main motor whose output power is great enough to withstand a heavy load.
Another conventional sheet feeding device includes a press drum having substantially the same outside diameter as the print drum in place of the press roller. The press drum scheme, however, has a problem that the timing for causing a registration roller pair to convey a sheet toward a sheet clamper is not accurate. As a result, the sheet is caused to roll up. Another problem is that the sheet clamper cannot surely clamp the leading edge of the sheet.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 5-330225, 8-332769, 9-1914, 5-305707 and 6-247586, Japanese Utility Model Publication No. 6-20620, and U.S. Pat. Nos. 5,415,387 and 4,911,069.